1. Field of the Invention
This invention relates to an improved construction of a wiper device for wiping the windowpanes of cars, ships, and the like.
2. Description of the Prior Art
FIG. 1 illustrates one of the wiper devices which have been publicly known. In this wiper device, a wiper motor 1 is arranged intermediate between supporting plates 6 and 6a in order to decrease the overall length of the rod, and links 3 and 4 are connected through a double pin 8 to a crank arm 2 which is driven and rotated by the wiper motor 1. The reciprocating movements of the links 3 and 4 are transmitted to the wiper blades (not shown) through ordinary connecting pins 9 and 10, shafts 5, and wiper arms 7, so that the wiper blades swing. To connect the links 3 and 4 to the crank arm 2, there is used the double pin 8 having a complicated shape shown in FIG. 2. The construction of the double pin 8 is as follows. A first ball portion 8a and a second ball portion 8b are machined by cutting and grinding from one workpiece, and a portion to be staked 8c is formed by the lower part of said second ball portion 8b. The portion to be staked 8c is securely fixed in a hole in the crank arm 2 with the use of staking, and a knurled portion 8d has a self-locking function so that the portion to be staked 8c can be firmly fixed to the crank arm 2 by staking. However, this double pin 8 suffers from a disadvantage that its complicated shape requires cutting and grinding operations resulting in a high manufacturing cost. Another disadvantage of the double pin 8 is that, when assembling the double pin 8 to the other parts, it is necessary to securely fix the portion to be staked 8c of the double pin 8 to the crank arm 2 by staking, slide the link 3 over the first ball portion 8a to fit the link 3 on the second ball portion 8b, and then fit the link 4 on the first ball portion 8a. This sequence of assembling steps is different from those for the connecting pins 9 and 10, and is disadvantageous from the standpoint of the unification of assembling steps. Although it is required that the shapes and assembling steps of the connecting pins be standardized and unified in order to accomplish a better control of materials and a higher assembling speed, the publicly known wiper device described above cannot meet such a requirement because it must use the double pin 8 which has a special construction and needs special assembling steps.